1. Field of the Invention
This application relates generally to evaporative coolers and more particularly to an evaporative cooler paired to a programmable controller system which is coupled to a wireless remote sensor unit which collects outside environmental data.
2. Brief Description of the Prior Art
Wireless transmission of data, and specifically environmental data such as temperature and humidity, has seen much in the way of prior art. The main use of this data has been in weather recording and reporting. An example of this prior art is U.S. Pat. No. 6,597,990, which discloses a weather detector and alarm. This use of prior art only reports and displays the transmitted data, whereas this invention also uses the data for process control.
Evaporative coolers, also known as swamp coolers are best suited to dry desert climates like that found in the southwestern United States. Evaporative coolers (FIG. 1) generally comprise a generally cubical metal structure of three to four feet in length, height, and width that is mounted on the exterior or roof of the building to be cooled. Three or four of the sides of the evaporative cooler comprise removable frames that contain pads 102 made of either natural or synthetic materials. The bottom of the evaporative cooler contains water 106 to a depth that is controlled by a float 104 to about four inches. The water is circulated by a water pump 105 through distribution tubes 107 to the tops of the pads to keep them wet. A blower fan 101,103 centrally located within the evaporative cooler pulls dry outside air 108 through the wet pads 102 and exhausts cooled air 110 into a duct distribution system 109 located within the building. Exemplary of such prior art evaporative coolers is that described in U.S. Pat. No. 4,379,712.
There are two significant problems with the prior art of evaporative coolers. The first is their high water usage, and the second is inability to respond to changing environmental conditions, creating a condition of high humidity inside the building being cooled.
Prior art evaporative coolers of the type commercially available are generally controlled by a simple rotary six position switch (FIG. 2) that allows the user to select a combination of water pump and blower fan settings. These manual switches are usually left in one position all day and do not address either of the previously mentioned problems. Manual control switches allow high water usage of approximately 15-20 gallons per hour and are unable to respond when outside conditions, such as rain or sunset, change the cooling requirements of the building.
There have been a number of attempts in the prior art to solve the problem of controlling evaporative cooler through the use of thermostats. Exemplary of the prior art are U.S. Pat. Nos. 4,232,531, 4,580,403, 4,673,028, and 4,4775,100. While providing an improvement over manual control, the use of line voltage thermostats have their own drawbacks. U.S. Pat. No. 4,4775,100 discloses a wide range of plus or minus 20 degrees Fahrenheit to prevent rapid cycling of the evaporative cooler, which allows hot outside air to enter the building. Since simple thermostat control turns on the water pump and blower fan at the same time, this will blow hot outside air into the building until the pads are properly wet. U.S. Pat. No. 5,031,412 has solved some of these problems by incorporating into a digital electronic controller, a thermostat and a real time clock. The clock allows for a cycle of pre-wetting the pads before starting the blower, and for starting and stopping the evaporative cooler at specific times of the day, such as morning or evening when outside temperatures are cooler. It is still unable to adapt to changing environmental conditions and may cause high interior humidity levels leading to personal discomfort, and possibly building damage, if left uncorrected.